In contrast to a barcode, which is one-dimensional in its nature and thus can be read using a line scan, the reading of a matrix code requires a two-dimensional image. The amount of light energy to obtain a well exposed two dimensional image is orders of magnitude greater than that needed for the one-dimensional nature of barcodes. Consequently, target illumination is the major power consumer in matrix code readers, and it limits their uptime between recharging or battery replacement.
In typical warehouse applications, boxes labeled with matrix codes sit on shelves and are thus stationary. The user points his or her device at a code in order to read it. Due to their unstable hand, the resulting motion of the device relative to the code will blur the code image, thereby making it useless unless a very short exposure is used to limit the motion blur. However, the shorter the exposure, the brighter the illumination that is needed. Reducing the required illuminating power would extend the device uptime and reduce, if not completely eliminate, the eye safety restrictions and their impact on device performance. Extending the exposure by one to two orders of magnitude may even allow operating the scanner using only ambient light.